Photostable Aggregation-Induced Emission Photosensitizer Nanoparticle/Hyaluronic Acid Hydrogel for Efficient Photodynamic Tooth Bleaching

In this work, a highly efficient photodynamic strategy for bleaching teeth was developed, and the strategy was based on aggregation-induced emission photosensitizer nanoparticles that were embedded in a hyaluronic acid hydrogel. The bleaching effect of the photosensitizer (PS) nanoparticle hydrogel was much better than that of the 40% H2O2 hydrogel used in the clinic. Both PSs exhibited an excellent photostability and ability to produce reactive oxygen species under light irradiation, and this significantly influenced the tooth bleaching effect. Upon white light irradiation, the increase in pulp cavity temperature remained under the safety threshold of 5.5 °C, which indicates that the photodynamic bleaching strategy is very safe. Furthermore, the microstructure damage in the enamel surface and the loss of minerals in the teeth were much less severe with this method than with the 40% H2O2 hydrogel treatment.